According to the American Cancer Society, approximately 560,000 Americans died from cancer during 2006, while 2007 brought an estimated 12 million new cancer cases worldwide. Although medical advances have improved cancer survival rates, there is a continuing need for new and more effective treatment.
Cancer is characterized by uncontrolled cell reproduction. Mitosis is a stage in the cell cycle during which a series of complex events ensure the fidelity of chromosome separation into two daughter cells. Several current cancer therapies, including the taxanes and vinca alkaloids, act to inhibit the mitotic machinery. Mitotic progression is largely regulated by proteolysis and by phosphorylation events that are mediated by mitotic kinases. Aurora kinase family members (e.g., Aurora A, Aurora B, Aurora C) regulate mitotic progression through modulation of centrosome separation, spindle dynamics, spindle assembly checkpoint, chromosome alignment, and cytokinesis (Dutertre et al., Oncogene, 21: 6175 (2002)); Berdnik et al., Curr. Biol., 12: 640 (2002)). Overexpression and/or amplification of Aurora kinases have been linked to oncogenesis in several tumor types including those of colon and breast (Warner et al., Mol. Cancer Ther., 2: 589 (2003); Bischoff et al., EMBO, 17: 3062 (1998); Sen et al., Cancer Res., 94: 1320 (2002)). Moreover, Aurora kinase inhibition in tumor cells results in mitotic arrest and apoptosis, suggesting that these kinases are important targets for cancer therapy (Ditchfield, J. Cell Biol., 161: 267 (2003); Harrington et al., Nature Med., 1 (2004)). Given the central role of mitosis in the progression of virtually all malignancies, inhibitors of the Aurora kinases are expected to have application across a broad range of human tumors.
WO 05/111039, U.S. Pat. No. 7,572,784, US Publication No. 2007/0185087, US Publication No. 2008/0045501, WO 08/063525, US Publication No. 2008/0167292, and US Publication No. 2010/0310651 hereby incorporated by reference in their entirety, disclose compounds that inhibit Aurora kinase enzymes. For example, the compound 4-{[9-chloro-7-(2-fluoro-6-methoxyphenyl)-5H-pyrimido[5,4-d][2]benzazepin-2-yl]amino}-2-methoxybenzoic acid of formula (II):
is a small molecule inhibitor of Aurora kinase.
These applications additionally disclose methods for the preparation of these compounds, pharmaceutical compositions containing these compounds, and methods for the prophylaxis and therapy of diseases, disorders, or conditions associated with overexpression and/or amplification of Aurora kinases, including, but not limited to, cell proliferative disorders such as cancer.
Sodium 4-{[9-chloro-7-(2-fluoro-6-methoxyphenyl)-5H-pyrimido[5,4-d][2]benzazepin-2-yl]amino}-2-methoxybenzoate (I) is described in WO 08/063525 and U.S. Ser. No. 08/0167292, herein incorporated by reference in their entirety. These references describe the synthesis of the compound of formula (I), which results in a mixture of crystalline forms, Form 1 and Form 2, of sodium 4-{[9-chloro-7-(2-fluoro-6-methoxyphenyl)-5H-pyrimido[5,4-d][2]benzazepin-2-yl]amino}-2-methoxybenzoate. These applications do not disclose other specific salts or crystalline forms of 4-{[9-chloro-7-(2-fluoro-6-methoxyphenyl)-5H-pyrimido[5,4-d][2]benzazepin-2-yl]amino}-2-methoxybenzoic acid (II).
The large-scale manufacturing of a pharmaceutical composition poses many challenges to the chemist and chemical engineer. While many of these challenges relate to the handling of large quantities of reagents and control of large-scale reactions, the handling of the final product poses special challenges linked to the nature of the final active product itself. Not only must the product be prepared in high yield, be stable, and capable of ready isolation, the product must possess properties that are suitable for the types of pharmaceutical preparations in which they are likely to be ultimately used. The stability of the active ingredient of the pharmaceutical preparation must be considered during each step of the manufacturing process, including the synthesis, isolation, bulk storage, pharmaceutical formulation and long-term formulation. Each of these steps may be impacted by various environmental conditions of temperature and humidity.
The pharmaceutically active substance used to prepare the pharmaceutical compositions should be as pure as possible, and its stability on long-term storage must be guaranteed under various environmental conditions. These properties are absolutely essential to prevent the appearance of unintended degradation products in pharmaceutical compositions, which degradation products may be potentially toxic or result simply in reducing the potency of the composition.
A primary concern for the manufacture of large-scale pharmaceutical compounds is that the active substance should have a stable crystalline morphology to ensure consistent processing parameters and pharmaceutical quality. If an unstable crystalline form is used, crystal morphology may change during manufacture and/or storage resulting in quality control problems, and formulation irregularities. Such a change may affect the reproducibility of the manufacturing process and thus lead to final formulations which do not meet the high quality and stringent requirements imposed on formulations of pharmaceutical compositions. In this regard, it should be generally borne in mind that any change to the solid state of a pharmaceutical composition which can improve its physical and chemical stability gives a significant advantage over less stable forms of the same drug.
When a compound crystallizes from a solution or slurry, it may crystallize with different spatial lattice arrangements, a property referred to as “polymorphism.” Each of the crystal forms is a “polymorph.” While polymorphs of a given substance have the same chemical composition, they may differ from each other with respect to one or more physical properties, such as solubility and dissociation, true density, melting point, crystal shape, compaction behavior, flow properties, and/or solid state stability.
As described generally above, the polymorphic behavior of drugs can be of great importance in pharmacy and pharmacology. The differences in physical properties exhibited by polymorphs affect practical parameters such as storage stability, compressibility and density (important in formulation and product manufacturing), and dissolution rates (an important factor in determining bio-availability). Differences in stability can result from changes in chemical reactivity (e.g., differential oxidation, such that a dosage form discolors more rapidly when it is one polymorph than when it is another polymorph) or mechanical changes (e.g., tablets crumble on storage as a kinetically favored polymorph converts to thermodynamically more stable polymorph) or both (e.g., tablets of one polymorph are more susceptible to breakdown at high humidity). In addition, the physical properties of the crystal may be important in processing: for example, one polymorph might be more likely to form solvates that cause the solid form to aggregate and increase the difficulty of solid handling, or might be difficult to filter and wash free of impurities (i.e., particle shape and size distribution might be different between one polymorph relative to other).
While drug formulations having improved chemical and physical properties are desired, there is no predictable means for preparing new drug forms (e.g., polymorphs) of existing molecules for such formulations. These new forms would provide consistency in physical properties over a range of environments common to manufacturing and composition usage. More particularly, there is a need for an inhibitor of Aurora kinase, including in particular Aurora A or B. Such an inhibitor should have utility in treating a patient suffering from or subject to Aurora kinase mediated pathological (diseases) conditions involving cell survival, proliferation and migration, including chronic inflammatory proliferative disorders, e.g., psoriasis and rheumatoid arthritis; proliferative ocular disorders, e.g., diabetic retinopathy; benign proliferative disorders, e.g., hemangiomas; and cancer, as well as having properties suitable for large-scale manufacturing and formulation.